Maybe this post will save somebody some time. Per SAP Support, this issue will not be fixed in release 2007A.
Users receive error 'Define Numbering Series in Administration module' for a properly defined secondary series numbers because they do not have rights to the default numbering series.
Client has two Purchasing and Sales document numbering series. Users with No Authorization to Series Group 1 cannot create documents in Series Group 2 even though they have Full Authorization to Series Group 2. They get the error above.
If I give these uses Full Authorization to Series Group 1 at
Admin > Sys Init > Numbering Series > Series Group 1
THEN they can create and save documents for Series Group 2. Of course they can now also create documents in Series Group 1, which is what I thought these settings were designed to prevent.